Lifting jack



Feb. 6, 1934. F. H. SCHWERIN LIFTING JACK Filed Nov. 21, 1931 m r z walum/$2 ATTORN E Patented Feb. 6, 1934 The invention relates t STAT-ES;PATENT OFFICE LIFTING JACK Frank H. Schwerin,

Bell'evue, Pa., assignor to- Application November 21, 1931 Serial No.576,512

2 Claims. (Cl. 254108) rack or ratchet jacks.

An object of the invention is to provide an improved jack having asimple and compact forcemultiplying mechanism including a compound leversystem and an operating handle" connected to the lever system in arelation which obtains the most desirable operation of theforce-multiplying mechanism. The invention is particularly adapted foruse in making the inspections of the journals of railway carsconveniently and quickly. Other objects, features and advantages of theinvention will appear or be pointed out as the description proceeds.

The embodiment of the invention illustrated in the accompanying drawingis shown partly in elevation and partly in ver tical section.

The jack frame comprises a base 2 and standard 3 rising from the baseand formed tangular passage for the which is formed with ratchet teeth5.

with a recjack bar 4, the back of At the back of the frame and extendingupward from the base is a rib 6, and above largement 7 containing Thetop of the jack this there is an enthe pawl mechanism.

bar is preferably provided with a lifting head 8, but the load restwhich is more the purpose of raising the particularly useful for cars isa long toe-lift 9,

truck-frames of railroad which projects at the say at the side opposite'mechanism. The front front of the jack, that is to from all theoperating wall of the standard is accordingly formed with a verticalslot 10 through which the toe-rest, secured to the lower end of the rackbar, extends.

Fulcrumed in the enlargement 7 on a pin 11 is these pawls vention thelever 12 is not front of the fulcrum, is

. A holding pawl 14 is enlargement on a pin 15. The arand of the lever12 may of the mechanisms of known cordance with this inthe operatinglever socketed to receive the handle but is a secondary lever of acompound leve The operating lever located below the lever 12.

the handle 17, and its forward for reception of r system.

19 of the present jack is It has the socket 16 portion is connected tothe rib 6 by a fulcrum pin 18. The two pair of links 20, constitutinglevers are interconnected by a the equivalent of a single link. Thelower ends of these links are pivoted on a pin 21, which is carried bythe primary operating lever at a point between its fulcrum 18 and thesocket are pivoted to a pin 22 ;;secondary lever 12, this ar 16. Theirupper ends on the rear end of the m of the secondary lever much longerthan the forward arm which distance between the centers of the fulcrum11 and the pivot of the pawl 13.

The socket 16 extends at an angle to a plane through the axes of thepivotal connections 18 and 21 so that the operators end of the handle1'7 is higher above the ground or floor on which the jack stands than itwould be if the axis of the socket and handle were in line with thesepivotal connections 18 and 21. In the drawing the pivot 21 is shown in apos'tion higher than the pivot 18. The angular relation of the handle1'! permits the operating lever 19 to be oscillated to bring the pivot21 well below the level of the pivot 18 before the operators end of thehandle 17 79 strikes the ground or floor.

The mechanical advantage of ratchet lifting jacks is not uniform. As thehandle 17 moves downward the lifting force of the jack decreasessomewhat because of changes in the effective lever arms. For example,the leverage effect of the operating lever 19 reaches a minimum when theaxes of the pivots 18 and 21 are in a substantially horizontal plane atright angles to the plane of the pivots 21 and 22. The most uniformmechanical advantage, and the greatest pawl travel, are obtained whenthe power stroke of the handle 1'? is such that the plane through theaxes of the pivots 18 and 21 becomes horizontal when the handle is atthe midpoint of its stroke.

The angular position of the socket 16 permits the use of a long handle1'7 and the most desirable stroke for the lever 19 with the axes of thepivots 18 and 21 in a substantially horizontal plane at the mid-strokeposition of the lever 19. Thus, the invention provides a jack having aminimum change in mechanical advantage during a stroke of the operatinglever.

This mechanism is a very simple and inexpensive means of increasing thepower advantage of the jack. It also possesses other distinctadvantages. The mechanism is all at the back of the jack and involves nooverhang or projection at the front which would keep the jack from beingplaced close to the face of a load to be raised on the toe-lift;consequently, the toe-lift can project from the front of the jack, andwhen this toe is used the operating lever and handle are away from theload. In geared rack jacks, in which multiplication of force is obtainedby gearing, the mechanism necessitates some projection beyond the frontor toe face of the jack, which increases the distance from the center ofthe jack bar to the load face, unless the toe is arranged to 1 being ismeasured by the project at one side :of the jack, as is sometimes done.In the latter event, however, the operating lever and handle mustoperate in a plane adjacent and'parallel with the load face, which insome work, such as journal work, would interfere with the side of thecar or other body.

In order to provide the jack with a larger base and to facilitate movingthe jack from point to point, a base plate 23 is attached to the base ofthe jack, upward rear extensions 24 of this base plate carrying twowheels 25, which when the jack is erect are clear of the ground. A catch26 pivoted on one of the links 20, or on a part of the jack frame, andengageable with a Stud 27 on the socket lever enables the handle to beused for tilting the jack and the 'base plate onto the support of thewheels for trundling.

It will be understood that jacks embodying the invention include meansfor reversing the pawl i action to secure automatic lowering of theload.

Known reversing provisions are applicable directly to the jack shown inthe drawing and it has been thought unnecessary to illustrate suchprovisions.

The jack of this invention is well adapted, and has been speciallydevised, for the inspection and repair of journals of railroad cars.Periodic inspection of all journals is compulsory, and a speeding up ofsuch inspections is greatly to be desired. The present jack is to beapplied to the truck frame between the journals, so that both journalsare raised and can be inspected at the same time. The force-multiplyinglinkage is such as to give ample power for this purpose with cars ofmaximum weight.

However; the invention is not confined to this use, and the jack may bereadily modified for other specific purposes.

I claim:

1. In a lifting jack, the combination with a the end of the long arm ofthe lever; a second lever fulcrumed at one end on the frame andpivotally connected intermediate its ends to the link at a point whichis higher than said fulcrum when the second lever is at one end of itsstroke; and a handle-receiving socket in the end of the second leverremote from the fulcrum, said socket extending upwardly at an angle whenthe parts are in such position that the fulcrum of the second lever andthe axis of its pivotal connection to the link are in a commonhorizontal plane.

2. In a lifting jack, the combination with a frame, of a ratchet barguided for vertical movement in the frame; force-multiplying mechanismcomprising a lever pivoted between its ends to the frame; a lifting pawlcarried by one end of the lever and engaging the teeth of the ratchetbar; a link pivotally connected to the other end of the lever; anoperating lever fulcrumed at one end on the frame and pivotallyconnected to the link at a point which is higher than the fulcrum whenthe mechanism is at one end of its stroke; and a handle connected to theoperating lever and extending at such an angle to a plane through thefulcrum and the axis of the pivotal connection of the operating lever tothe link that the handle has a substantial upward slope when theoperating lever is moved into position where said fulcrum and axis arein a common horizontal plane.

FRANK H. SCHWERIN.

